This method, also known under the term “bolt setting,” is a forming jointing method, in which the nail (bolt) is driven at a high speed into the components to be joined. It has the advantage that in general one-sided accessibility of the joint area suffices and preholing operations can often be avoided. Bolt setting is already used as a reliable jointing method in many areas like steel construction, facade construction, metal construction, ship construction and building construction.
For example, nails (setting bolts) that are driven into steel, structural iron, sheet metal and similar metallic materials by means of setting devices in the form of powder-power-driven cartridges are known from DE 1 575 152, 1 940 447, 1 500 770. Such a nail normally consists of a nail head, a nail shank and an ogival nail point, wherein the shank can be provided with a surface profiling in the form of cross or arrow knurls, spiral running ribbings and the like.
A nail (bolt) with a flat head, a cylindrical shank and an ogival nail point, which serves to fasten sheets to a metal part that is stronger than the sheet, is known from DE-GM 72 26 710. The nail is shot into the metal part through a prefabricated hole in the sheet. A recess for receiving the material protruding out of it during the shooting into the metal part is provided in the head and/or in the shank of the nail. In accordance with one embodiment of this document, the recess is provided on the bottom side of the nail head so that the edge of the sheet surrounding the prefabricated hole is bent up into the recess by the displaced material of the metal part. The metal part, the thickness of which is considerably greater than the length of the nail, completely surrounds the nail point. The method disclosed in this document above all serves to fasten name plates on machines. This jointing method is not suitable for the fastening of sheets on extrusion profiles with a closed cross-section or on internal-high-pressure-reshaped components such as required for example in vehicle construction.
GB 1 479 600 describes a jointing method, in which a screw with a nail point is shot into two sheets. With the help of this method, the two sheets are neither fastened together nor is the screw permanently inserted so that it connects the two sheets reliably. Instead a preholing is replaced by the shooting in of the screw with a nail point, in that after being shot in the screw must be screwed tightly into the two sheets and thereby fastened. In the case of this type of fastening of the two sheets together, the plurality of process steps to be executed is a disadvantage. Furthermore, it is questionable whether the thread of the screw actually forms a reliable connection with the hole shot into the sheets.
A jointing method suitable for this purpose is for example the so-called direct fastening, also called “Flow Drilling Screw” (FDS). In this process (see e.g. DE 102 48 427 A1, DE 39 22 684 A1, DE 39 09 725 C1 and DE 196 37 969 C2), a screw with a flat screw head, a screw shank provided with a thread and a screw point is used. The screw is first installed at a high speed and with a corresponding contact pressure on the components to be joined. The frictional heat hereby occurring plasticizes the joined part material to be formed. Crater-like or toric appendages, in which the screw thread grooves out a counter thread, are hereby formed both opposite and in the feed direction. The screw-in process is complete when the screw has penetrated the components and the screw head is set on the upper component.